Appliance for indicating explosive pressures in gas-engines.



'0. P. LOOMIS.

APPLIANCE FOR INDICATING EXPLOSIVE PRESSURES IN GAS ENGINES.

- Patented June 22, 1915..

APPLICATION FIL ED MAR- l3| I909.

V/Qia .of improvement.

,pipe H having at its end screwed through the bottom A and h OSBORN P. LOOMIS, 0F NEWPORT NEWS, VIRGINIA.

APPLIANCE JFOR INDICATING EXPLOSIVE PRESSUBES IN GAS-ENGINES.

Specification of Letters Patent. Patentmfl Jun a 22, 19115,,

Application filedMarch 13, 1909. Serial No. 483,096.

T all whom it may concern Be it known that I, OsBoRN P. a citizen of the United States, residing at Newport News, in the county of Warwick and State of Virginia, have invented certain new and useful Improvements in Appliances for Indicating Explosive Pressures in Gas- Engines, of which the following is a specification.

The object of my invention is to provide a device by which the pressures at which gasengines are operating can be conveniently ascertained. This information enables the engineer to tell at once whether proper pressures are being developed in the explosive space of the engine cylinder, and in the case of multiple cylinders enables him to ascertain if all are alike in efi ort, if any are lacking, and to what extent. The usual way of ascertaining these pressures is by means of the steam-engine indicator. While this instrument afi'ords accurate results, its use is attended by much trouble and inconvenience and it does not afford continuous indications of pressure. I have accordingly devised an arrangement which will secure this result and the following is a description of the same, reference being had to the accompanying drawing, in which the figure is a view in elevation, parts being, for convenience, shown in section.

In my prior Patent No. 1,087,883, patented Feb. 17, 1914, I have shown and described a damping device for pressure gages which can and has been used for indicating pressures in explosive engine cylinders, but the following invention has certain features LooMIs,

Referring to the drawings, Figure 1 is a view in elevation, parts being shown in section; Figs. 2, 3, 4 and 5 show modified forms of valve.-

In Fig. 1 of the drawing, 1 is a pressure gage of any usual type which is connected to a casing 5, this casing being divided by a diaphragm M into two chambers A and D. The lower chamber A which may be termed the sediment-collecting chamber receives the pressure gases from the engine through a an extension E oi the chamber avmg its openin at t e'u er art thereof and in proximitg to the lib tton i of the diaphragm M. The bottom ofthis chamber A is provided with an opening normally closed by a stop-cock F. The soot, carbonized material, etc., carried from the engine cylinder by the gases arev thrown against the bottom of the partition M and drop down into the chamber A, whence they can be blown out occasionally along with the water which is always present, by opening the cock F. The pressure gases pass from thechamber A upward through the pipe G, secured to the diaphragm M, and thence into the pipe B which is coiled as shown to provide an extended frictional surface for the gases flowing therethrough. The combined throttling and cushioning effect produced by the pipe B and the expansion or air chamber D prevents any violent fiuctuations of the gage needle and makes it practically dead beat. The operation of this portion of the device is the same as that disclosed in my prior application above referred to; p

The gases are admitted from the engine cylinder to the pipe H through a retardative return valve J which is mounted in a valve-casing, the lower part 2 of which is provided with a boreI, opening into a chamber 9 which is in turn closed by a plug 3, into which is screwed a coupling 10 which connects the valve-casing with the pipe H. In case it is not convenient to make connection at the top of the valve the connection can be made at the opening clpsed by the plug K, the opening in the top being then of course correspondingly plugged.

The valve J which is constructed to permit free flow of pressure gases in one direction and to greatly retard the flow in the other, is, as shown, seated on the bottom of the chamber 9 in such a position as to normally close the bore ll. An increase of pressurein the engine cylinder causes the valve to rise and allows the pressure to be transmitted through the openings 4 into the tube H.

As the pressures of a gas engine are pulsating, and at times even non-existent, t is desirable to secure the highest indications possible on the gage in order to detect small differences in cylinder pressures, by which leaks, imperfect firing and other defects are discovered. These results are accomplished by the valve which has just been mentioned.

When the engine is started the valve J is lifted and allows the pressure to pass around its stem and enter-the space above it, and thence to be exerted through the plpe H through the damping chambers to the gage. After a few explosions the pressure on top of the valve J (which retards the gas from returning during small intervals) will reach a maximum for a given load at which the engine is operating. Should the explosive pressures in the cylinder then increase, the valve J will allow it to enter the pipe H which will be indicated by a rise of the gage pointer. Should the explosive pressures within the cylinder decrease, the pressure in the pipe H (and consequently on the gage) will also decrease, due to the fact that the tightness of the valve J is designedly made imperfect and slowly allows'thev pressure to leak space until a certain definite relation between the two pressures is reached.

-By the combination of parts it is apparent that there is afforded a continuous dead beat indication of a pressure bearing a certain relation to that actually occurring in the cylinder at the time indicated. Practical results show that these indicated pressures are not initial, neither are they mean effective pressure, but are somewhere between the two.

While I have described the apparatus as particularly adapted for use in connection with the indication of gas-engine pressures, it is of course equally adapted for use in any locality where the measurement of pulsating and widely varying pressures is desired.

While I may, as abovedescribed, rely upon the leakage of the valve J vto permit release of pressure within the gage mechanism, I may provide a small leak opening or vent through the body of the valve itself. This vent may be, as shown in Fig. 2, a fine bore K, through the body of the valve J As holes of such small diameter as are required for this purpose, are diflicult to make, I can arrive at the same result by the means shown in Fig. 3, in. which the bore K through the body of the valve J a is made of considerable size, and the ends are partially closed as shown by setting over the edges of the openings at the ends of the bore with asuitable tool. Or I may make the bore K through the stem of the valve of a diameter convenient to drill, and then roll down a portion of the stem to contract the inside bore to the extent desired,the end of the main bore being contracted as shown I in Fig. 4, or left of its original diameter.

The mode of operation of the valve provided with the leak vent, is substantially the same as described with reference to the construction shown in Fig. 1. The leak vent is so small as not to permit, during the intervals between the pulsations of pressure, any diminution of pressure sufiicient to affect the practical accuracy of the gage indications,while the leak so obtained does serve back into the explosive upper ends of the pins sired.

to allow with suflicient rapidity, the escape of compressed gas in the system so that the gage may indicate a decreased or fallen pressure occurring in the cylinder.

Instead of providing the valve with a leak vent, or relying upon the usual leakage of the valve, I may adopt the form of vented retardative return valve shown in valve seat, thereby preventing the valve,

from fitting with entire snugness to its seat. Moreover, as the pins do not fit into the holes with absolute exactness, a slight passageway for the gases exists between the and the holes, thereby assisting to afford the slight leakage de- This form of leakage valve precludes the possibility of the leak-vents being closed by fine material in suspension in the steam or hot gases. The operation of this form of valve is the same as that before described.

' The direct connection of the leakage-valve casing to the source of explosive pressure, as in automobile engines, is particularly advantageous, as the actual pressure in the engine cylinder is thereby indicated without the diminution, due to friction in the connecting pipe, which occurs if the leakage-valve is located at or near the gage. It is to be noted further that as there is no leakage to the outer air there is no possibility of loss of residual pressure in the engine cylinder, should the engine be temporarily stopped, and the necessity of frequent recranking is thereby avoided.

In operating gas engines of considerable size, it has been found that small pockets or clearance spaces leading from the cylinder are liable to hold flame and cause what is known as back firing which is the ignition and exploding of the mixture in the cylinder before the proper time in the stroke and seriously retarding the operation of the engine. In making connections for indicators to cylinders of gas engines such openings are necessary and I find that with. my system ofpressure indicators as described in this specification, attached. to such openings the slight return-leakage of a compressed gas, cooled by the exposure of the pipe H and air chamber casing 5, obviates the difliculty of back firing as it is evident that a small portion of the cooled highly compressedgas leaking into the clear- .nected chamber being provided with means for remeans ance space through the passage I, expands many times and pushes into the exhaustthe hot gases andflame that may be contained therein and at the same time cooling the lining ignite.

, I claim:

1. In combination, a casing having therein two chambers connected together by a flow retarding passage, one chamber being conto a pressure gage and the other moving collected sediment. 2. In combination, a reservoir having therein two chambersconnected together by a throttled passage, one chamber being connected to. a pressure-gage, and the other chamber being provided with a pipe for delivering pressure-gases thereinto, and means for removing sedii ent from such chamber. 3. The combination of a valve-casing adapted to be connected to an engine-'cylin:

der, a retardative return valve in such casing, a pipe connected-thereto and arranged to deliver into the lower or sediment cham ber of a gage mechanism, such mechanism comprising a gage, a casing to which the gage is connected, an apertured partition so that any further mixture will' not 1 'in two chambers connected dividing the easing into two chambers, a flow-retarding device opening into the upper chamber and means for permitting remom of sediment from the, lower chamber.

4. In combination, a casing-having theretogether by a throttled passage, one chamber being connected to a gage and the other chamber being provided with deflecting surfaces arranged to throw awaythe sediment from the gases passing toward the gage.

5. In a fluid-pressure actuated pressure gage, a closed cushion chamber having an indicating mechanism directly connected thereto, a chamber for pressure fluid, a conduit containing a throttled section connecting the two chambers, a pipe for connecting the pressure fluid chamber to an engine-cylinder, to permit free flow of pressure gases in one direction and to greatly retard the flow in the other.-

In testimony whereof, I afi'ix my signa ture in presence of two witnesses.

OSBORN P. LOOMIS. Witnesses: v

N. L. HAWKINs, FRANK W. W001).

anda valve in such pipe constructed. 

